'use strict'

const noopServiceWorkerMiddleware = require('react-dev-utils/noopServiceWorkerMiddleware')
const config                      = require('./webpack.config.dev')
const paths                       = require('./paths')

const protocol = process.env.HTTPS === 'true' ? 'https' : 'http'
const host     = process.env.HOST || '0.0.0.0'

module.exports = function(proxy, allowedHost) {
	return {
	    // WebpackDevServer 2.4.3 introduced a security fix that prevents remote
	    // websites from potentially accessing local content through DNS rebinding:
	    // https://github.com/webpack/webpack-dev-server/issues/887
	    // https://medium.com/webpack/webpack-dev-server-middleware-security-issues-1489d950874a
	    // However, it made several existing use cases such as development in cloud
	    // environment or subdomains in development significantly more complicated:
	    // https://github.com/facebookincubator/create-react-app/issues/2271
	    // https://github.com/facebookincubator/create-react-app/issues/2233
	    // While we're investigating better solutions, for now we will take a
	    // compromise. Since our WDS configuration only serves files in the `public`
	    // folder we won't consider accessing them a vulnerability. However, if you
	    // use the `proxy` feature, it gets more dangerous because it can expose
	    // remote code execution vulnerabilities in backends like Django and Rails.
	    // So we will disable the host check normally, but enable it if you have
	    // specified the `proxy` setting. Finally, we let you override it if you
	    // really know what you're doing with a special environment variable.
		disableHostCheck: !proxy || process.env.DANGEROUSLY_DISABLE_HOST_CHECK === 'true',

   		// Enable gzip compression of generated files.
		compress: true,

	    // Silence WebpackDevServer's own logs since they're generally not useful.
	    // It will still show compile warnings and errors with this setting.
		clientLogLevel: 'none',

	    // By default WebpackDevServer serves physical files from current directory
	    // in addition to all the virtual build products that it serves from memory.
	    // This is confusing because those files won’t automatically be available in
	    // production build folder unless we copy them. However, copying the whole
	    // project directory is dangerous because we may expose sensitive files.
	    // Instead, we establish a convention that only files in `public` directory
	    // get served. Our build script will copy `public` into the `build` folder.
	    // In `index.html`, you can get URL of `public` folder with %PUBLIC_URL%:
	    // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
	    // In JavaScript code, you can access it with `process.env.PUBLIC_URL`.
	    // Note that we only recommend to use `public` folder as an escape hatch
	    // for files like `favicon.ico`, `manifest.json`, and libraries that are
	    // for some reason broken when imported through Webpack. If you just want to
	    // use an image, put it in `src` and `import` it from JavaScript instead.
		contentBase: paths.appPublic,

    	// By default files from `contentBase` will not trigger a page reload.
		watchContentBase: true,

	    // Enable hot reloading server. It will provide /sockjs-node/ endpoint
	    // for the WebpackDevServer client so it can learn when the files were
	    // updated. The WebpackDevServer client is included as an entry point
	    // in the Webpack development configuration. Note that only changes
	    // to CSS are currently hot reloaded. JS changes will refresh the browser.
		hot: true,

    	// It is important to tell WebpackDevServer to use the same "root" path
    	// as we specified in the config. In development, we always serve from /.
		publicPath: config.output.publicPath,

    	// WebpackDevServer is noisy by default so we emit custom message instead
    	// by listening to the compiler events with `compiler.plugin` calls above.
		quiet: true,

    	// Reportedly, this avoids CPU overload on some systems.
    	// https://github.com/facebookincubator/create-react-app/issues/293
		watchOptions: {
			ignored: /node_modules/,
		},

    	// Enable HTTPS if the HTTPS environment variable is set to 'true'
		https: protocol === 'https',

		host: host,
		overlay: true,
		historyApiFallback: {
      		// Paths with dots should still use the history fallback.
      		// See https://github.com/facebookincubator/create-react-app/issues/387.
			disableDotRule: true,
		},

		public: allowedHost,
		proxy,

		setup(app) {
			// This service worker file is effectively a 'no-op' that will reset any
			// previous service worker registered for the same host:port combination.
			// We do this in development to avoid hitting the production cache if
			// it used the same host and port.
			// https://github.com/facebookincubator/create-react-app/issues/2272#issuecomment-302832432
			app.use(noopServiceWorkerMiddleware())
		},
	}
}
